1. Field
Embodiments relate to an organic light emitting diode display and a fabricating method thereof.
2. Description of the Related Art
An organic light emitting diode (OLED) display is a flat panel display that may be lightweight and thin, may exhibit a self-luminous characteristic, and may not require a separate light source. The OLED display may exhibit quality characteristics, e.g., low power consumption, high luminance, and high response speed, and as such, the OLED display is receiving much attention as a next-generation display device.
An organic light emitting diode display may include an organic light emitting diode including an anode, an organic emission layer, and a cathode. Holes and electrons may be injected from the anode and the cathode, respectively, to form excitons. The excitons may transition to a ground state, thereby causing the organic light emitting diode to emit light.
A lifespan of such an organic light emitting diode may be limited. For example, the lifespan of the organic light emitting diode may be affected by degradation of organic materials, interfacial characteristics of organic materials, and so on. A method for improving interfacial characteristics by forming a buffer layer under each pixel in order to improve the lifespan of an organic light emitting diode has been proposed.
For example, the organic light emitting diode may include a red pixel (R), a green pixel (G), and a blue pixel (B); and the lifespan varies from pixel to pixel. To compensate for differences in lifespan among pixels, each pixel may include a buffer layer formed thereunder. For example, thickness of the respective buffer layers may differ from pixel to pixel.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. SUMMARY
Embodiments are directed to an organic light emitting diode display and a fabricating method thereof.
At least one of the above and other features and advantages may be realized by providing an organic light emitting diode display including a substrate; a thin film transistor on the substrate; and an organic light emitting diode on the substrate, the organic light emitting diode including a pixel electrode, an organic emission layer, and a common electrode, wherein the organic emission layer includes a red (R) pixel, a green (G) pixel, and a blue (B) pixel, the pixel electrode includes a first pixel electrode, a second pixel electrode, and a third pixel electrode that respectively correspond to the red pixel, the green pixel, and the blue pixel, the first pixel electrode, the second pixel electrode, and the third pixel electrode each have different thicknesses, and the first pixel electrode, the second pixel electrode, and the third pixel electrode each include a first hydrophobic layer.
A thickness of the first pixel electrode may be greater than a thickness of the second pixel electrode, and a thickness of the second pixel electrode may be greater than a thickness of the third pixel electrode.
The first pixel electrode may include a sequentially stacked first ITO (indium tin oxide) layer, Ag (silver) layer, second ITO layer, third ITO layer, and fourth ITO layer, the first hydrophobic layer may be between the second ITO layer and the third ITO layer, and the first pixel electrode may further include a second hydrophobic layer, the second hydrophobic layer being between the third ITO layer and the fourth ITO layer.
The first ITO layer, the second ITO layer, and the third ITO layer may each include polycrystalline ITO.
The second pixel electrode may include a sequentially stacked first ITO layer, Ag layer, second ITO layer, and third ITO layer, and the first hydrophobic layer may be between the second ITO layer and the third ITO layer.
The second pixel electrode may further include a second hydrophobic layer, the second hydrophobic layer being on the third ITO layer.
The first ITO layer, the second ITO layer, and the third ITO layer may each include polycrystalline ITO.
The third pixel electrode may include a sequentially stacked first ITO layer, Ag layer, and second ITO layer, and the first hydrophobic layer may be on the second ITO layer.
The first ITO layer and the second ITO layer may each include polycrystalline ITO.
The first hydrophobic layer may have a thickness of about 30 Å to about 50 Å.
The organic emission layer may further include at least one of a hole injection layer, a hole transporting layer, an electron transporting layer, and an electron injection layer.
The organic light emitting diode display may further include a reflective layer on the common electrode.
At least one of the above and other features and advantages may also be realized by providing a fabricating method of an organic light emitting diode display, the method including providing a substrate; forming a thin film transistor on the substrate; forming a pixel electrode on the thin film transistor; forming an organic emission layer on the pixel electrode; and forming a common electrode on the organic emission layer, wherein the pixel electrode includes a first hydrophobic layer and a second hydrophobic layer, and thicknesses of portions of the pixel electrode corresponding to a red pixel, a green pixel, and a blue pixel of the organic emission layer, respectively, are different from each other.
Forming the pixel electrode may include forming a first pixel electrode, a second pixel electrode, and a third pixel electrode under each of and corresponding to the red pixel, the green pixel, and the blue pixel, respectively, a thickness of the first pixel electrode may be greater than a thickness of the second pixel electrode, and a thickness of the second pixel electrode may be greater than a thickness of the third pixel electrode.
Forming the pixel electrode may include sequentially stacking a first ITO layer, a Ag layer, and a second ITO layer; forming the first hydrophobic layer on the second ITO layer; forming a third ITO layer on the first hydrophobic layer; removing a part of the third ITO layer; forming the second hydrophobic layer on the third ITO layer; forming a fourth ITO layer on the second hydrophobic layer; and removing a part of the fourth ITO layer.
Forming the pixel electrode may further include polycrystallizing the first ITO layer and the second ITO layer prior to forming the first hydrophobic layer.
Polycrystallizing the first ITO layer and the second ITO layer may include a heat treatment.
Removing the part of the third ITO layer may include forming a photoresist layer on portions of the third ITO layer corresponding to the red pixel and the green pixel; etching portions of the third ITO layer corresponding to the blue pixel; and removing the photoresist layer.
Forming the pixel electrode may further include polycrystallizing the third ITO layer prior to forming the second hydrophobic layer.
Polycrystallizing the third ITO layer may include a heat treatment.
Removing the part of the fourth ITO layer may include forming a photoresist layer on a portion of the fourth ITO layer corresponding to the red pixel; etching portions of the fourth ITO layer corresponding to the green pixel and the blue pixel; and removing the photoresist layer.
The first hydrophobic layer and the second hydrophobic layer may each have a thickness of about 30 Å to about 50 Å.